All three major stock indexes were up, with the S&P 500 at a four-month high.

At 4:30 p.m., the API is scheduled to release its U.S. inventory data for last week. Analysts expect inventories to have declined.

Last month, the United States said it wanted to reduce oil exports of fifth-biggest producer Iran to zero by November.

Still, Brent was buoyed by a strike by hundreds of workers on Norwegian offshore oil and gas rigs, leading to the shutdown of one Shell-operated oilfield.

Also bullish to prices was plummeting production in Libya, where output has halved in five months to 527,000 barrels per day.

“Working in the opposite direction of the Norwegian oil workers strike and the geopolitical situation” was the update on the Syncrude oil sands facility, said Yawger at Mizuho.

On Monday, Suncor Energy said its 360,000-barrel-per-day Syncrude facility would resume some production in July, earlier than expected, following an outage last month that disrupted total output and sent U.S. prices higher.

The updated timeline has muted U.S. price gains and widened the difference between the two benchmarks, said Yawger.

Meanwhile, members of the Organisation of the Petroleum Exporting Countries, led by Saudi Arabia, have agreed to boost output.

Still, there is concern that doing so will use up global spare capacity and leave markets vulnerable to further or unexpected production declines. (Reuters/NAN)